1985 305 2v to 2001 4v vortec swap ?

bgiese

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Apr 18, 2009
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I have a 1985 Chris Craft scorpion 186, it came with a 305 2 barrel carb and all stock equipment as far as exhaust and carb etc. I'm changing this engine out for a 2001 5.7 vortec from a malibu ski boat, it has the carter electric fuel pump,holley 600 dual feed carb and the indmar/malibu aluminum high rise intake. so far I have installed a 12 inch flywheel in place of the 2001 14 inch one, new coupler, engine water pump and most every other part that can be swapped over from the origanal 305. now comes the part were I've ran into a snag, the malibu intake moves the thermostat housing about 2 1/2 inches forward toward the water pump, when test fitting the origanal thermostat housing from the 305, it places the inlet coming from the sterndrive thru the powersteering cooler right on top of the pulley on the water pump, while getting some parts from michiganmotorz, discussed this with them and ended up with a shotneck thermostat housing which looks like it could work but it has only 2 ports routing water to the exhaust manifolds not 4 like my origanal one had. My question is can I eliminate the hoses running to the exhaust elbow assembly and only use the ones running to the lower side of the exhaust manifolds or do I need to put in a tee of some kind and route water to the manifolds prior to going thru the thermostat housing, I have seen the type of hookup in a mercruiser service manual that they only run water to the exhaust manifold not the exhaust elbow but is this a different type of elbow/manifold arrangement or different material, I guess I'm almost to the point of changing the intake for a performer air gap intake and peddling the indmar/malibu. so was hoping maybe someone had put this type of intake on a alpha one drive and 3 inch center rise exhaust manifolds before and could let me know what they did to hook every thing up.
thanks for any help it will be appreciated
Bgiese
 

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Bondo

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Re: 1985 305 2v to 2001 4v vortec swap ?

Ayuh,... Where's the T-Stat housing off the Indmar,..??
The T-Stat don't care how you plumb the Manifolds, but the Manifolds care....
If it can be plumbed with only 2 lines,... That's what I'd do...
The picture of the T-Stat housing is from the wrong side to see the Problem...

Does the block have the drillings for the 12" flywheel's Starter,..??
I know some have Both patterns,+ others Don't...
 

bgiese

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Re: 1985 305 2v to 2001 4v vortec swap ?

Bond-o
the original housing never came with the engine, I have one from michiganmotorz that is for a indmar application. the real issue with the 1985 thermostat housing was it put the inlet right on top of the pulley on the water pump, did get in touch with a guy from there late last night, he said that I can plumb it to the lower manifold connection and plug off the one in the exhaust elbow, but may have to change the gasket between the manifold and the elbow if it isn't a full flow kind, so I guess I will move toward that direction. the 12 inch flywheel is already on along with the original starter from the 1985 305, so far all I have had to do was chase alot of threads in mounting holes that were not used when it was mounted in the malibu, the only issue I believe that I have left will be the cooling hoses and wiring for the electric fuel pump. Thanks for the response
Bgiese
 

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fstncrnrs

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Re: 1985 305 2v to 2001 4v vortec swap ?

i am considering the same swap. i was wondering about exhaust manifolds port shapes. i think the heads on the 5.3 are oval port and not sure how they will bolt up with old style manifolds. if this swap works let me no. i just scattered my 350 this memorial day weekend.
 

Bondo

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Re: 1985 305 2v to 2001 4v vortec swap ?

i am considering the same swap. i was wondering about exhaust manifolds port shapes. i think the heads on the 5.3 are oval port and not sure how they will bolt up with old style manifolds. if this swap works let me no. i just scattered my 350 this memorial day weekend.

No,... Nope,.... It's Not the Same swap you want to do....
Quit posting in the archives,+ start a thread of your Own, about what you Want to do...
As I've posted a couple times now,...
Your dream Ain't gonna Happen,... The 5.3l Chevy is NOT an option for you....
 
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